Experimental and numerical study of stitching interferometry for the optical testing of the SPICA Telescope

Hidehiro Kaneda; Masataka Naitoh; Tadashi Imai; Haruyoshi Katayama; Takashi Onaka; Takao Nakagawa; Mitsunobu Kawada; Mitsuyoshi Yamagishi; Takuma Kokusho

doi:10.1117/12.926879

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21 September 2012 Experimental and numerical study of stitching interferometry for the optical testing of the SPICA Telescope

Hidehiro Kaneda, Masataka Naitoh, Tadashi Imai, Haruyoshi Katayama, Takashi Onaka, Takao Nakagawa, Mitsunobu Kawada, Mitsuyoshi Yamagishi, Takuma Kokusho

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Proceedings Volume 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave; 84423T (2012) https://doi.org/10.1117/12.926879
Event: SPIE Astronomical Telescopes + Instrumentation, 2012, Amsterdam, Netherlands

Abstract

SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is a Japan-led infrared astronomical satellite project with a 3.2-m lightweight cryogenic telescope. The SPICA telescope has stringent requirements such as that for the imaging performance to be diffraction-limited at the shortest core wavelength of 5 microns at the operating temperature of 6 K. The design of the telescope system has been studied by the Europe-Japan telescope working group led by ESA with the European industries, the results of which will be presented in other papers. We here present our recent optical testing activities in Japan for the SPICA telescope, focusing on the experimental and numerical studies of stitching interferometry. The full pupil of the SPICA telescope will be covered by a sub-pupil array consisting of small autocollimating flat mirrors (ACFs), which are rotated with respect to the optical axis of the telescope. For preliminary stitching experiments, we have fabricated an 800-mm lightweight telescope all made of the C/SiC called HBCesic, which is a candidate mirror material for the SPICA telescope, and started optical testing with 900-mm and 300-mm ACFs at an ambient temperature. ACFs can suffer significant surface deformation in testing a telescope at cryogenic temperatures, which is difficult to be measured directly. We therefore investigate the effects of the surface figure errors of the ACFs on stitching results by numerical simulation.

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Hidehiro Kaneda, Masataka Naitoh, Tadashi Imai, Haruyoshi Katayama, Takashi Onaka, Takao Nakagawa, Mitsunobu Kawada, Mitsuyoshi Yamagishi, and Takuma Kokusho "Experimental and numerical study of stitching interferometry for the optical testing of the SPICA Telescope", Proc. SPIE 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, 84423T (21 September 2012); https://doi.org/10.1117/12.926879

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